Quantitative analysis on forest resource management along with environmental conservation and economic development in mountainous areas

该项目的目标是对山区森林资源管理以及环境保护和经济发展进行沿着定量分析。我们的结果是：1.成本分析：在目前的木材价格水平下，可能无法进行造林和采伐。在使用补贴的情况下，再植仍然存在困难。因此，有必要更新和修改补贴政策，以实现我国森林资源的可持续管理.最优间伐制度：利用所提出的动态规划模型，揭示了补贴对间伐的管理效应。补贴越多，最佳轮伐期往往越长，最长可达40年。将贴现率从1%改变到3%，观察到1%和2%的影响较大，而3%几乎没有影响。木材需求/供给模型：在宫崎作为最大的杉生产国之一，国内木材需求的相对价格弹性为-4.6，弹性很大。在岩手县，原木需求的相对价格弹性为-0.29。静冈靠近主要的木材消费国，表现出更好的结果，木材供应。4森林资源管理：基于目前的森林蓄积水平，我们分析了多少木材供应可以预期的可持续的方式随着时间的推移，使用基于LP的采伐模型。在宫崎，允许10%的收获流量周期性变化，定期（5年）收获水平为949万m^3，在30%的允许量下，广岛为209.5万m^3。这是因为与主要木材生产国相比，广岛的生产基础设施并不发达，宫崎，也因为美国原木大量进口，意味着国内木材生产环境没有改善的必要。

The objective of the project was to conduct quantitative analysis on forest resource management along with environmental conservation and economic development in mountainous areas. Our results are :1. Cost analysis : Under the current level of timber price level, silvicultural and harvesting practices may not be carried out. With use of subsidies there still remains difficulty for replantation. As a result, it will be necessary to renew and modify the subsidy policy in order to achieve our sustainable forest resorce management.2. Optimal thinning regime : With use of the proposed dynamic programming model, management effect of subsidy on thinning was revealed. The more the subsidy, optimal rotation age tends to be longer, ending up to 40 years. Changing discount rate from 1 to 3%, large effect was observed for 1 and 2% as compared to almost no effect for 3%.3. Timber demand/supply modeling : In Miyazaki as one of the largest sugi producing states, relative price elasticity of domestic lumber demand was -4.6, very elastic. In Iwate, relative price elasticity of log demand was -0.29. Shizuoka, which is close to the major timber consuming states, showed better results on timber supply.4 Forest resource management : Based on the current forest stocking level, we analyzed how much of timber supply could be expected on the sustainable fashion over time by use of the LP based harvesting model. In Miyazaki, allowing 10% change in harvest flow period by period, periodical (5 years) harvest level became 9490,000 m^3, which that was 2095,000 m^3 for Hiroshima under 30% allowance. This is because in Hiroshima infrastructure for production is not well developed as opposed to the major timber producing states, e.g., Miyazaki, and also because a large amount of US logs is imported, implying no necessity of improvement for domestic timber producing environments.